The invention relates to an apparatus for metering viscous compositions.
Metering apparatuses for metering viscous compositions are known. The viscous composition, which is to be metered, is supplied with the help of a pump, connected upstream from the metering chamber, over a delivery line to the metering chamber of the metering apparatus. The pump takes the viscous composition, for example, from a container. When filling the metering chamber, an inlet valve, which is disposed between the pump and the metering chamber, is opened, while the outlet valve, which is connected downstream from the metering chamber, is closed. After the metering chamber is filled, the inlet valve is closed and the valve opened.
A displacer, which is disposed in the metering chamber and, when the latter is being filled, moves into a position, in which the metering chamber has its largest volume, is moved with the help of a driving mechanism, such as an electric motor, into the metering chamber, so that the viscous composition, contained in the metering chamber, is displaced and discharged through the opened outlet valve to a delivery point.
When the displacer has reached a position, in which the metering chamber has its smallest volume, an amount of the viscous composition, corresponding to the displacement volume of the displacer, has been delivered to the removal site. Subsequently, the outlet valve is closed and the inlet valve opened, and the displacer is moved back to the starting position. The metering chamber is filled once again by the conveying action of the pump.
For the metering apparatus of the type named above, the metering chamber and the driving mechanism for the displacer, which can be shifted longitudinally in the metering chamber, represent two separate units, which are connected with one another over a driving element, such as a belt drive. This leads to a relatively bulky and expensive construction.